During a recent congressional hearing, Rep. Steve King of Iowa underestimated what scientists know about the relationship between farming practices and water quality.

King said scientists don’t know about the quality of water in the U.S. “when the buffalo roamed” because there were “no water quality tests then.” Pre-1900 water quality data is relatively scarce, but experts can use techniques from paleolimnology to evaluate past water quality.

He implied that this lack of “baseline” data prevents scientists from knowing whether applications of crop fertilizer are “too much.” But experts say they don’t need 19th century data to know fertilizers have negatively impacted water quality. The 20th century provides plenty of evidence.

In case you didn’t watch the Academy Awards last night – spoiler alert – Leonardo DiCaprio finally won Best Actor for The Revenant! Whether that matters to you or not, Leo continued his vocal stance on climate change and mentioned it in-depth in his acceptance speech!! He also posted about climate change on his Facebook wall, and included MomentForAction.org (below). Check out previous CauseScience posts on Leo killing it in a speech at the UN Climate Summit, and being named UN Messenger of Peace on Climate Change! Leo is definitely the biggest celebrity that continually vocalizes concern for climate change and repeatedly demands action!! Maybe this all started when he realized that Titanic could only happen in a world with icebergs 😉 (FANGIRLING!)

If you haven’t been keeping up, Flint, Michigan has been in the news lately due to its toxic tap water. Two years ago, to cut costs, the state decided to switch Flint’s water supply from Lake Huron (which they were paying the city of Detroit for), to the Flint River, a notorious tributary that runs through town known to locals for its filth. The results are not surprising.

Turns out the water is highly toxic, and highly corrosive. Researchers discovered more than double the normal levels of lead in children’s blood samples. From the Washington Post:

My $0.02… when it comes to health and safety, it is wise to NOT cut costs. As a result of trying to save some money, now Flint is dealing with far greater issues including irreversible damage to the health of its residents and water supply infrastructure. Fixing these problems will be far more costly…

In the past, these Republican candidates have disparaged the idea of global warming. “We’re not going to make America a harder place to create jobs in order to pursue policies that will do absolutely nothing, nothing, to change our climate,” Marco Rubio said in a Republican debate in September.

Donald Trump uttered this marvel: “I am not a believer, and I will, unless somebody can prove something to me, I believe there’s weather. I believe there’s change, and I believe it goes up and it goes down, and it goes up again.”

Ted Cruz, who seems enthralled with the idea of a climate-science conspiracy, said last week, “Climate change is the perfect pseudoscientific theory for a big-government politician who wants more power.” On Saturday, Mr. Cruz had nothing to say.

Let’s hope the candidates’ new silence suggests that they see that when 195 nations together recognize the need for immediate action, their arguments to do nothing seem more misguided than ever.

While everyone is in Paris working on climate talks, Beijing has issued their first ever “red alert” due to smog in the city. This heightened level of pollution has forced school closings, factory closings, and limited car usage. From the BBC:

The alert, the highest possible warning level, was issued late Monday and will last until midday on Thursday.

Limits have been placed on car use and some factories have been ordered to stop operations.

It comes as China, the world’s worst polluter, takes part in talks on carbon emissions in Paris.

It is the first time China has declared a red alert under the four-tier alert system, which was adopted a little over two years ago, although pollution levels were far from the city’s worst.

At 07:00 local time on Tuesday (23:00 GMT on Monday), when the alert came into effect, the US Embassy’s air pollution monitor in Beijing reported that the intensity of the tiny particles known as PM 2.5 was at 291 micrograms per cubic metre.

By 11:00 it had dropped very slightly to 250 – still a level it described as “very unhealthy”. Levels of the poisonous particles in the suburbs were reported at several times that number.

The World Health Organization recommends 25 micrograms per cubic metre as the maximum safe level.

Near the East 4th Ring Road, facing west towards Beijing on 1 December…

… and the same location a day later

Not only is this scary, but it’s a huge warning to those in Paris that something serious needs to be done in order to curb climate change.

Today marks the beginning of a two-week long U.N. climate conference in Paris. Despite the recent terrorist attacks, leaders from around the world (including Obama) will be there with the goals of passing world-wide measures to halt climate change. NPR provides a list of 10 things to know about the conference:

1. What’s at stake and why should I care?

It’s no exaggeration to say that what happens in Paris will affect the future of the planet. Greenhouse gas emissions keep going up, and scientists say that continuing with business as usual will produce rapid and devastating warming. This won’t just be bad news for polar bears and beachfront homeowners. Unchecked warming means that dependable food and water supplies could be disrupted, dangerous pathogens could spread to new areas, and rising seas could remake maps. What’s more, extreme weather, plus worse droughts and more fierce wildfires, could become increasingly common. Security experts even worry that scarce and shifting resources could lead to violence.

2. What needs to happen to stop climate change?

Many nations want a Paris agreement that will signal a long-term goal of net zeroemissions in the second half of this century. That doesn’t mean actually producing zero greenhouse gas emissions. But it does mean producing no more than the planet can absorb without raising temperatures. Doing this would mean a dramatic transformation of the world’s entire energy system, turning away from fossil fuels to other options like wind, solar and nuclear power. The task is absolutely staggering — but scientists say it can be done, if the political will is there.

3. Well, is there really the political will to do all this?

U.N. watchers say the stars are aligned like never before. Before the summit, all countries — rich and poor — were asked to come forward with their own voluntary pledges for how they would aid the global fight against climate change. Over 150 countries have submitted national plans to the U.N., and that in and of itself is a huge deal. Some nations say how they’ll cut emissions, while others pledge to do things like preserve forest cover or use more clean energy. Independent experts have calculated that if the world is currently on track for warming of about 4.5 degrees Celsius, these pledges would reduce that to about 2.7 to 3.7 degrees — which is real progress, before the Paris summit even starts.

4. What does the Paris agreement really need to have in it?

The goal of Paris is to produce a short, simple agreement — maybe a dozen pages — that will satisfy nearly 200 nations. Here’s what some observers think are key elements for a credible, ambitious plan forward:

Countries need to agree to come back every few years to increase their pledges and keep doing more and more to reduce greenhouse gas emissions

The U.N. must have a rigorous system of accountability and transparency to make sure nations will actually keep their promises

The poorest countries of the world need support to both adapt to a warming world and to adopt new, low-carbon energy technologies

5. There’s talk of a 2 degree Celsius warming limit. Will this agreement hit that target?

That target comes from an international consensus five years ago, when nations agreed to limit warming to just about 2 degrees Celsius (about 3.5 degrees Fahrenheit) over pre-industrial times. The thinking was that this would avert the worst effects of climate change. But no one thinks Paris will get the world that far. Instead, the aim of Paris is to come up with an agreement that requires countries to make increasingly ambitious efforts to combat global warming over time, to put the world on track to meet that target in the future.

6. Rich and poor countries are all part of this thing, but will rich countries have to do more?

There’s a lot of tension between the developed world and the developing world when it comes to climate change. Some developing countries such as India say they’re in no position to commit to an absolute reduction in greenhouse gases when they’re trying to bring economic advancement to millions of people who currently live in poverty. They need a supply of energy, and lots of it. What’s more, poorer nations want financial compensation if they’re going to agree to do things like preserve rain forests that will suck up carbon dioxide. They note that developed nations chopped down their own trees long ago and have burned enormous amounts of fossil fuels, but now they’re being told they can’t do the same — so they think the developed world should pay up. So-called “financing” issues will be a major hurdle that negotiators will have to clear in Paris.

7. How is the U.N. trying to make this deal happen?

Basically, for two weeks, they’re going to sequester a bunch of diplomats in a conference center outside Paris. There’s been years of preparation leading up to this conference, and organizers expect tens of thousands of people to gather. Besides the delegates and diplomats there to do the actual wrangling, tons of businesses, activist organizations and scientists will be there as well. While some outside events may be curtailed because of the recent terrorist attacks, the negotiations should go on as scheduled.

8. But, hey, hasn’t the U.N. been trying to rein in greenhouse gas emissions for two decades?

It’s certainly true that past efforts have had serious shortcomings. Top emitters like the United States refused to join the landmark 1997 Kyoto Protocol, and it didn’t include any developing countries, like China. Then the 2009 Copenhagen summit ended in a shambles, with a weak agreement thrown together at the last minute by politicians who didn’t want to leave the talks with nothing. But things are different this time. The fact that almost all countries have submitted voluntary pledges shows that governments feel pressure to participate. Both the United States and China have taken a leadership role. And major public figures like Pope Francis have been urging action, saying there’s a moral duty.

9. What are the big fights going on in the negotiations?

Besides arguing over how much rich nations should pay the poor, there are some nations that simply are not excited about a zero carbon future. Oil- and gas-producing countries, for example, aren’t so keen to leave their valuable assets in the ground. Another hot-button issue is “loss and damage.” That’s the idea that there should be some mechanism to compensate the citizens of places that simply cannot adapt to climate change — for example, small island states that could disappear under rising seas.

10. What if Paris ends with a whimper?

Scientists say that delaying action is just going to make changes harder and more expensive in the future, and that really the world should have started this transformation decades ago. If reliance on fossil fuels continues and produces unrestrained climate change, experts predict dramatic shifts in our familiar maps and weather patterns. Computer simulations show that New York would have the climate of Miami, and melting ice would flood major cities around the world. Poor countries would be the hardest hit by a changing world, as they have the fewest resources to adapt.

Making the moral case on climate change ahead of Paris summit

Much of the general public is well aware of scientists’ recommendations on climate change. In particular, climate scientists and other academics say society needs to keep global temperatures to no more than two degrees Celsius below preindustrial levels to avoid the most dangerous effects of climate change.

But now more academics are weighing in on climate change: philosophers, ethicists, and social scientists among others.

More than 2,100 academics, and counting, from over 80 nations and a diversity of disciplines have endorsed a moral and political statement addressed to global leaders ahead of December’s UN climate conference in Paris.

As one of the philosophers responsible for this open letter, along with my colleague Keith Horton (University of Wollongong, Australia), I wish to explain why we felt compelled to organize it and why the endorsement of many influential philosophers is important.

In addition to Chomsky and Singer, the list of prominent philosophers who have converged from various philosophical backgrounds and points of disagreement to endorse this letter include many of the most influential figures in contemporary moral and political philosophy.

Thinking about the real world

While it may be popular among certain politicians to malign academics as removed from the “real world,” the fact remains that academics by virtue of training and professional necessity are driven to distinguish valid argument and sound evidence from fallacy.

We are bound to reference current research, and to examine our data before making claims if we hope to be taken seriously by our peers. We have a pedagogical obligation to instill these same practices in our students. We also have a moral obligation to prepare them for responsible citizenship and careers.

Global warming is the most important moral issue of our time, and arguably the greatest existential threat that human beings, as a whole, have faced. So the response to climate change from philosophers should be no surprise.

Those most responsible for climate change are relatively few compared to the vast numbers of people who will be harmfully affected. Indeed, climate change will, in one way or another, impact all life on Earth.

If we fail to decisively address the problem now, warming may escalate in a relatively short time beyond the point which human beings can reasonably be expected to cope, given the nature of reinforcing feedback effects.

The moral implications are enormous, and this letter represents the closest we have to a consensus statement from the world’s preeminent professional ethicists on some of the moral obligations industrial nations, and their leaders, have to global communities, future generations, and fellow species. The letter begins:

Some issues are of such ethical magnitude that being on the correct side of history becomes a signifier of moral character for generations to come. Global warming is such an issue. Indigenous peoples and the developing world are least responsible for climate change, least able to adapt to it, and most vulnerable to its impacts. As the United Nations Climate Conference in Paris approaches, the leaders of the industrialized world shoulder a grave responsibility for the consequences of our current and past carbon emissions.

Importantly, the letter points out that even if current nonbinding pledges being offered by world leaders ahead of the conference are achieved, we remain on course to reach potentially catastrophic levels of warming by the end of this century. The letter continues:

This is profoundly shocking, given that any sacrifice involved in making those reductions is far overshadowed by the catastrophes we are likely to face if we do not: more extinctions of species and loss of ecosystems; increasing vulnerability to storm surges; more heatwaves; more intense precipitation; more climate related deaths and disease; more climate refugees; slower poverty reduction; less food security; and more conflicts worsened by these factors. Given such high stakes, our leaders ought to be mustering planet-wide mobilization, at all societal levels, to limit global warming to no more than 1.5 degree Celsius.

It is increasingly obvious as we head to Paris that both industrialized and developing nations must make serious efforts to limit their greenhouse gas emissions beyond their current pledges. This is a requirement of physics.

It is unrealistic to expect most developing nations to meaningfully limit greenhouse gas emissions without binding pledges from industrialized nations to do so, as well as significant commitments to provide financial and technological assistance to poorer nations facing developmental challenges. This is a practical necessity and a requirement of ethics.

Ethical thinking

At its most fundamental level, thinking ethically means taking the interests of others seriously enough to recognize when our actions and omissions must be justified to them.

As individuals, our instincts too often drive us toward self-interest. Consequently, acting ethically beyond the circle of our immediate relations – that is, those we perceive most capable of reciprocating both harms and benefits – is difficult.

Still, the history of our species teaches that humanity as a whole benefits most when we are able to put narrow self-interest aside, and make an ethical turn in our thinking and behavior.

Now, faced with climate change the next great ethical turn in our thinking and behavior can’t come soon enough. We will make progress in addressing climate change when, and if, we begin taking the lessons of morality seriously.